A technology of encoding data to be stored in a memory in a predetermined coding unit (for example, a block size unit) is well known in order to reduce a use amount of the memory such as a DRAM (Dynamic Random Access Memory) and a transfer amount of a bus connected to the memory. The coded data encoded by the technology is read from the memory in the same read unit (for example, the block size unit) as the coding unit.
However, the read unit is conventionally the block size unit even if a data size requested by a data processing module that performs data processing is smaller than a block size. Accordingly, utilization efficiency of the bus is decreased in reading the coded data from the memory.
On the other hand, if the read unit becomes smaller than the block size unit, utilization efficiency of the bus is improved. However, it is necessary to make the coding unit smaller for making the read unit smaller than the block size unit. Quality of data obtained by decoding the coded data is degraded if the coding unit size is reduced.